1 /* $OpenBSD: sshconnect2.c,v 1.319 2020/02/06 22:30:54 naddy Exp $ */ 2 /* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 #include <sys/wait.h> 32 #include <sys/stat.h> 33 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <netdb.h> 37 #include <pwd.h> 38 #include <signal.h> 39 #include <stdio.h> 40 #include <string.h> 41 #include <stdarg.h> 42 #include <unistd.h> 43 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS) 44 #include <vis.h> 45 #endif 46 47 #include "openbsd-compat/sys-queue.h" 48 49 #include "xmalloc.h" 50 #include "ssh.h" 51 #include "ssh2.h" 52 #include "sshbuf.h" 53 #include "packet.h" 54 #include "compat.h" 55 #include "cipher.h" 56 #include "sshkey.h" 57 #include "kex.h" 58 #include "myproposal.h" 59 #include "sshconnect.h" 60 #include "authfile.h" 61 #include "dh.h" 62 #include "authfd.h" 63 #include "log.h" 64 #include "misc.h" 65 #include "readconf.h" 66 #include "match.h" 67 #include "dispatch.h" 68 #include "canohost.h" 69 #include "msg.h" 70 #include "pathnames.h" 71 #include "uidswap.h" 72 #include "hostfile.h" 73 #include "ssherr.h" 74 #include "utf8.h" 75 #include "ssh-sk.h" 76 #include "sk-api.h" 77 78 #ifdef GSSAPI 79 #include "ssh-gss.h" 80 #endif 81 82 /* import */ 83 extern char *client_version_string; 84 extern char *server_version_string; 85 extern Options options; 86 87 /* 88 * SSH2 key exchange 89 */ 90 91 u_char *session_id2 = NULL; 92 u_int session_id2_len = 0; 93 94 char *xxx_host; 95 struct sockaddr *xxx_hostaddr; 96 97 static int 98 verify_host_key_callback(struct sshkey *hostkey, struct ssh *ssh) 99 { 100 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 101 fatal("Host key verification failed."); 102 return 0; 103 } 104 105 static char * 106 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 107 { 108 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 109 size_t maxlen; 110 struct hostkeys *hostkeys; 111 int ktype; 112 u_int i; 113 114 /* Find all hostkeys for this hostname */ 115 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 116 hostkeys = init_hostkeys(); 117 for (i = 0; i < options.num_user_hostfiles; i++) 118 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 119 for (i = 0; i < options.num_system_hostfiles; i++) 120 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 121 122 oavail = avail = xstrdup(kex_default_pk_alg()); 123 maxlen = strlen(avail) + 1; 124 first = xmalloc(maxlen); 125 last = xmalloc(maxlen); 126 *first = *last = '\0'; 127 128 #define ALG_APPEND(to, from) \ 129 do { \ 130 if (*to != '\0') \ 131 strlcat(to, ",", maxlen); \ 132 strlcat(to, from, maxlen); \ 133 } while (0) 134 135 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 136 if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC) 137 fatal("%s: unknown alg %s", __func__, alg); 138 if (lookup_key_in_hostkeys_by_type(hostkeys, 139 sshkey_type_plain(ktype), NULL)) 140 ALG_APPEND(first, alg); 141 else 142 ALG_APPEND(last, alg); 143 } 144 #undef ALG_APPEND 145 xasprintf(&ret, "%s%s%s", first, 146 (*first == '\0' || *last == '\0') ? "" : ",", last); 147 if (*first != '\0') 148 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 149 150 free(first); 151 free(last); 152 free(hostname); 153 free(oavail); 154 free_hostkeys(hostkeys); 155 156 return ret; 157 } 158 159 void 160 ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port) 161 { 162 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; 163 char *s, *all_key; 164 int r; 165 166 xxx_host = host; 167 xxx_hostaddr = hostaddr; 168 169 if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL) 170 fatal("%s: kex_names_cat", __func__); 171 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s); 172 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 173 compat_cipher_proposal(options.ciphers); 174 myproposal[PROPOSAL_ENC_ALGS_STOC] = 175 compat_cipher_proposal(options.ciphers); 176 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 177 myproposal[PROPOSAL_COMP_ALGS_STOC] = 178 (char *)compression_alg_list(options.compression); 179 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 180 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 181 if (options.hostkeyalgorithms != NULL) { 182 all_key = sshkey_alg_list(0, 0, 1, ','); 183 if (kex_assemble_names(&options.hostkeyalgorithms, 184 kex_default_pk_alg(), all_key) != 0) 185 fatal("%s: kex_assemble_namelist", __func__); 186 free(all_key); 187 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 188 compat_pkalg_proposal(options.hostkeyalgorithms); 189 } else { 190 /* Enforce default */ 191 options.hostkeyalgorithms = xstrdup(kex_default_pk_alg()); 192 /* Prefer algorithms that we already have keys for */ 193 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 194 compat_pkalg_proposal( 195 order_hostkeyalgs(host, hostaddr, port)); 196 } 197 198 if (options.rekey_limit || options.rekey_interval) 199 ssh_packet_set_rekey_limits(ssh, options.rekey_limit, 200 options.rekey_interval); 201 202 /* start key exchange */ 203 if ((r = kex_setup(ssh, myproposal)) != 0) 204 fatal("kex_setup: %s", ssh_err(r)); 205 #ifdef WITH_OPENSSL 206 ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client; 207 ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client; 208 ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client; 209 ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client; 210 ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client; 211 ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 212 ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 213 # ifdef OPENSSL_HAS_ECC 214 ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client; 215 # endif 216 #endif 217 ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client; 218 ssh->kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_client; 219 ssh->kex->verify_host_key=&verify_host_key_callback; 220 221 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &ssh->kex->done); 222 223 /* remove ext-info from the KEX proposals for rekeying */ 224 myproposal[PROPOSAL_KEX_ALGS] = 225 compat_kex_proposal(options.kex_algorithms); 226 if ((r = kex_prop2buf(ssh->kex->my, myproposal)) != 0) 227 fatal("kex_prop2buf: %s", ssh_err(r)); 228 229 session_id2 = ssh->kex->session_id; 230 session_id2_len = ssh->kex->session_id_len; 231 232 #ifdef DEBUG_KEXDH 233 /* send 1st encrypted/maced/compressed message */ 234 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 235 (r = sshpkt_put_cstring(ssh, "markus")) != 0 || 236 (r = sshpkt_send(ssh)) != 0 || 237 (r = ssh_packet_write_wait(ssh)) != 0) 238 fatal("%s: %s", __func__, ssh_err(r)); 239 #endif 240 } 241 242 /* 243 * Authenticate user 244 */ 245 246 typedef struct cauthctxt Authctxt; 247 typedef struct cauthmethod Authmethod; 248 typedef struct identity Identity; 249 typedef struct idlist Idlist; 250 251 struct identity { 252 TAILQ_ENTRY(identity) next; 253 int agent_fd; /* >=0 if agent supports key */ 254 struct sshkey *key; /* public/private key */ 255 char *filename; /* comment for agent-only keys */ 256 int tried; 257 int isprivate; /* key points to the private key */ 258 int userprovided; 259 }; 260 TAILQ_HEAD(idlist, identity); 261 262 struct cauthctxt { 263 const char *server_user; 264 const char *local_user; 265 const char *host; 266 const char *service; 267 struct cauthmethod *method; 268 sig_atomic_t success; 269 char *authlist; 270 #ifdef GSSAPI 271 /* gssapi */ 272 gss_OID_set gss_supported_mechs; 273 u_int mech_tried; 274 #endif 275 /* pubkey */ 276 struct idlist keys; 277 int agent_fd; 278 /* hostbased */ 279 Sensitive *sensitive; 280 char *oktypes, *ktypes; 281 const char *active_ktype; 282 /* kbd-interactive */ 283 int info_req_seen; 284 int attempt_kbdint; 285 /* password */ 286 int attempt_passwd; 287 /* generic */ 288 void *methoddata; 289 }; 290 291 struct cauthmethod { 292 char *name; /* string to compare against server's list */ 293 int (*userauth)(struct ssh *ssh); 294 void (*cleanup)(struct ssh *ssh); 295 int *enabled; /* flag in option struct that enables method */ 296 int *batch_flag; /* flag in option struct that disables method */ 297 }; 298 299 static int input_userauth_service_accept(int, u_int32_t, struct ssh *); 300 static int input_userauth_ext_info(int, u_int32_t, struct ssh *); 301 static int input_userauth_success(int, u_int32_t, struct ssh *); 302 static int input_userauth_failure(int, u_int32_t, struct ssh *); 303 static int input_userauth_banner(int, u_int32_t, struct ssh *); 304 static int input_userauth_error(int, u_int32_t, struct ssh *); 305 static int input_userauth_info_req(int, u_int32_t, struct ssh *); 306 static int input_userauth_pk_ok(int, u_int32_t, struct ssh *); 307 static int input_userauth_passwd_changereq(int, u_int32_t, struct ssh *); 308 309 static int userauth_none(struct ssh *); 310 static int userauth_pubkey(struct ssh *); 311 static int userauth_passwd(struct ssh *); 312 static int userauth_kbdint(struct ssh *); 313 static int userauth_hostbased(struct ssh *); 314 315 #ifdef GSSAPI 316 static int userauth_gssapi(struct ssh *); 317 static void userauth_gssapi_cleanup(struct ssh *); 318 static int input_gssapi_response(int type, u_int32_t, struct ssh *); 319 static int input_gssapi_token(int type, u_int32_t, struct ssh *); 320 static int input_gssapi_error(int, u_int32_t, struct ssh *); 321 static int input_gssapi_errtok(int, u_int32_t, struct ssh *); 322 #endif 323 324 void userauth(struct ssh *, char *); 325 326 static void pubkey_cleanup(struct ssh *); 327 static int sign_and_send_pubkey(struct ssh *ssh, Identity *); 328 static void pubkey_prepare(Authctxt *); 329 static void pubkey_reset(Authctxt *); 330 static struct sshkey *load_identity_file(Identity *); 331 332 static Authmethod *authmethod_get(char *authlist); 333 static Authmethod *authmethod_lookup(const char *name); 334 static char *authmethods_get(void); 335 336 Authmethod authmethods[] = { 337 #ifdef GSSAPI 338 {"gssapi-with-mic", 339 userauth_gssapi, 340 userauth_gssapi_cleanup, 341 &options.gss_authentication, 342 NULL}, 343 #endif 344 {"hostbased", 345 userauth_hostbased, 346 NULL, 347 &options.hostbased_authentication, 348 NULL}, 349 {"publickey", 350 userauth_pubkey, 351 NULL, 352 &options.pubkey_authentication, 353 NULL}, 354 {"keyboard-interactive", 355 userauth_kbdint, 356 NULL, 357 &options.kbd_interactive_authentication, 358 &options.batch_mode}, 359 {"password", 360 userauth_passwd, 361 NULL, 362 &options.password_authentication, 363 &options.batch_mode}, 364 {"none", 365 userauth_none, 366 NULL, 367 NULL, 368 NULL}, 369 {NULL, NULL, NULL, NULL, NULL} 370 }; 371 372 void 373 ssh_userauth2(struct ssh *ssh, const char *local_user, 374 const char *server_user, char *host, Sensitive *sensitive) 375 { 376 Authctxt authctxt; 377 int r; 378 379 if (options.challenge_response_authentication) 380 options.kbd_interactive_authentication = 1; 381 if (options.preferred_authentications == NULL) 382 options.preferred_authentications = authmethods_get(); 383 384 /* setup authentication context */ 385 memset(&authctxt, 0, sizeof(authctxt)); 386 authctxt.server_user = server_user; 387 authctxt.local_user = local_user; 388 authctxt.host = host; 389 authctxt.service = "ssh-connection"; /* service name */ 390 authctxt.success = 0; 391 authctxt.method = authmethod_lookup("none"); 392 authctxt.authlist = NULL; 393 authctxt.methoddata = NULL; 394 authctxt.sensitive = sensitive; 395 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; 396 authctxt.info_req_seen = 0; 397 authctxt.attempt_kbdint = 0; 398 authctxt.attempt_passwd = 0; 399 #if GSSAPI 400 authctxt.gss_supported_mechs = NULL; 401 authctxt.mech_tried = 0; 402 #endif 403 authctxt.agent_fd = -1; 404 pubkey_prepare(&authctxt); 405 if (authctxt.method == NULL) { 406 fatal("%s: internal error: cannot send userauth none request", 407 __func__); 408 } 409 410 if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 || 411 (r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 || 412 (r = sshpkt_send(ssh)) != 0) 413 fatal("%s: %s", __func__, ssh_err(r)); 414 415 ssh->authctxt = &authctxt; 416 ssh_dispatch_init(ssh, &input_userauth_error); 417 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info); 418 ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept); 419 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt.success); /* loop until success */ 420 pubkey_cleanup(ssh); 421 ssh->authctxt = NULL; 422 423 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 424 425 if (!authctxt.success) 426 fatal("Authentication failed."); 427 debug("Authentication succeeded (%s).", authctxt.method->name); 428 } 429 430 /* ARGSUSED */ 431 static int 432 input_userauth_service_accept(int type, u_int32_t seq, struct ssh *ssh) 433 { 434 int r; 435 436 if (ssh_packet_remaining(ssh) > 0) { 437 char *reply; 438 439 if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0) 440 goto out; 441 debug2("service_accept: %s", reply); 442 free(reply); 443 } else { 444 debug2("buggy server: service_accept w/o service"); 445 } 446 if ((r = sshpkt_get_end(ssh)) != 0) 447 goto out; 448 debug("SSH2_MSG_SERVICE_ACCEPT received"); 449 450 /* initial userauth request */ 451 userauth_none(ssh); 452 453 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error); 454 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 455 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 456 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 457 r = 0; 458 out: 459 return r; 460 } 461 462 /* ARGSUSED */ 463 static int 464 input_userauth_ext_info(int type, u_int32_t seqnr, struct ssh *ssh) 465 { 466 return kex_input_ext_info(type, seqnr, ssh); 467 } 468 469 void 470 userauth(struct ssh *ssh, char *authlist) 471 { 472 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 473 474 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 475 authctxt->method->cleanup(ssh); 476 477 free(authctxt->methoddata); 478 authctxt->methoddata = NULL; 479 if (authlist == NULL) { 480 authlist = authctxt->authlist; 481 } else { 482 free(authctxt->authlist); 483 authctxt->authlist = authlist; 484 } 485 for (;;) { 486 Authmethod *method = authmethod_get(authlist); 487 if (method == NULL) 488 fatal("%s@%s: Permission denied (%s).", 489 authctxt->server_user, authctxt->host, authlist); 490 authctxt->method = method; 491 492 /* reset the per method handler */ 493 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_PER_METHOD_MIN, 494 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 495 496 /* and try new method */ 497 if (method->userauth(ssh) != 0) { 498 debug2("we sent a %s packet, wait for reply", method->name); 499 break; 500 } else { 501 debug2("we did not send a packet, disable method"); 502 method->enabled = NULL; 503 } 504 } 505 } 506 507 /* ARGSUSED */ 508 static int 509 input_userauth_error(int type, u_int32_t seq, struct ssh *ssh) 510 { 511 fatal("%s: bad message during authentication: type %d", __func__, type); 512 return 0; 513 } 514 515 /* ARGSUSED */ 516 static int 517 input_userauth_banner(int type, u_int32_t seq, struct ssh *ssh) 518 { 519 char *msg = NULL; 520 size_t len; 521 int r; 522 523 debug3("%s", __func__); 524 if ((r = sshpkt_get_cstring(ssh, &msg, &len)) != 0 || 525 (r = sshpkt_get_cstring(ssh, NULL, NULL)) != 0) 526 goto out; 527 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) 528 fmprintf(stderr, "%s", msg); 529 r = 0; 530 out: 531 free(msg); 532 return r; 533 } 534 535 /* ARGSUSED */ 536 static int 537 input_userauth_success(int type, u_int32_t seq, struct ssh *ssh) 538 { 539 Authctxt *authctxt = ssh->authctxt; 540 541 if (authctxt == NULL) 542 fatal("%s: no authentication context", __func__); 543 free(authctxt->authlist); 544 authctxt->authlist = NULL; 545 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 546 authctxt->method->cleanup(ssh); 547 free(authctxt->methoddata); 548 authctxt->methoddata = NULL; 549 authctxt->success = 1; /* break out */ 550 return 0; 551 } 552 553 #if 0 554 static int 555 input_userauth_success_unexpected(int type, u_int32_t seq, struct ssh *ssh) 556 { 557 Authctxt *authctxt = ssh->authctxt; 558 559 if (authctxt == NULL) 560 fatal("%s: no authentication context", __func__); 561 562 fatal("Unexpected authentication success during %s.", 563 authctxt->method->name); 564 return 0; 565 } 566 #endif 567 568 /* ARGSUSED */ 569 static int 570 input_userauth_failure(int type, u_int32_t seq, struct ssh *ssh) 571 { 572 Authctxt *authctxt = ssh->authctxt; 573 char *authlist = NULL; 574 u_char partial; 575 576 if (authctxt == NULL) 577 fatal("input_userauth_failure: no authentication context"); 578 579 if (sshpkt_get_cstring(ssh, &authlist, NULL) != 0 || 580 sshpkt_get_u8(ssh, &partial) != 0 || 581 sshpkt_get_end(ssh) != 0) 582 goto out; 583 584 if (partial != 0) { 585 verbose("Authenticated with partial success."); 586 /* reset state */ 587 pubkey_reset(authctxt); 588 } 589 debug("Authentications that can continue: %s", authlist); 590 591 userauth(ssh, authlist); 592 authlist = NULL; 593 out: 594 free(authlist); 595 return 0; 596 } 597 598 /* 599 * Format an identity for logging including filename, key type, fingerprint 600 * and location (agent, etc.). Caller must free. 601 */ 602 static char * 603 format_identity(Identity *id) 604 { 605 char *fp = NULL, *ret = NULL; 606 const char *note = ""; 607 608 if (id->key != NULL) { 609 fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 610 SSH_FP_DEFAULT); 611 } 612 if (id->key) { 613 if ((id->key->flags & SSHKEY_FLAG_EXT) != 0) 614 note = " token"; 615 else if (sshkey_is_sk(id->key)) 616 note = " authenticator"; 617 } 618 xasprintf(&ret, "%s %s%s%s%s%s%s", 619 id->filename, 620 id->key ? sshkey_type(id->key) : "", id->key ? " " : "", 621 fp ? fp : "", 622 id->userprovided ? " explicit" : "", note, 623 id->agent_fd != -1 ? " agent" : ""); 624 free(fp); 625 return ret; 626 } 627 628 /* ARGSUSED */ 629 static int 630 input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh) 631 { 632 Authctxt *authctxt = ssh->authctxt; 633 struct sshkey *key = NULL; 634 Identity *id = NULL; 635 int pktype, found = 0, sent = 0; 636 size_t blen; 637 char *pkalg = NULL, *fp = NULL, *ident = NULL; 638 u_char *pkblob = NULL; 639 int r; 640 641 if (authctxt == NULL) 642 fatal("input_userauth_pk_ok: no authentication context"); 643 644 if ((r = sshpkt_get_cstring(ssh, &pkalg, NULL)) != 0 || 645 (r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 || 646 (r = sshpkt_get_end(ssh)) != 0) 647 goto done; 648 649 if ((pktype = sshkey_type_from_name(pkalg)) == KEY_UNSPEC) { 650 debug("%s: server sent unknown pkalg %s", __func__, pkalg); 651 goto done; 652 } 653 if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) { 654 debug("no key from blob. pkalg %s: %s", pkalg, ssh_err(r)); 655 goto done; 656 } 657 if (key->type != pktype) { 658 error("input_userauth_pk_ok: type mismatch " 659 "for decoded key (received %d, expected %d)", 660 key->type, pktype); 661 goto done; 662 } 663 664 /* 665 * search keys in the reverse order, because last candidate has been 666 * moved to the end of the queue. this also avoids confusion by 667 * duplicate keys 668 */ 669 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 670 if (sshkey_equal(key, id->key)) { 671 found = 1; 672 break; 673 } 674 } 675 if (!found || id == NULL) { 676 fp = sshkey_fingerprint(key, options.fingerprint_hash, 677 SSH_FP_DEFAULT); 678 error("%s: server replied with unknown key: %s %s", __func__, 679 sshkey_type(key), fp == NULL ? "<ERROR>" : fp); 680 goto done; 681 } 682 ident = format_identity(id); 683 debug("Server accepts key: %s", ident); 684 sent = sign_and_send_pubkey(ssh, id); 685 r = 0; 686 done: 687 sshkey_free(key); 688 free(ident); 689 free(fp); 690 free(pkalg); 691 free(pkblob); 692 693 /* try another method if we did not send a packet */ 694 if (r == 0 && sent == 0) 695 userauth(ssh, NULL); 696 return r; 697 } 698 699 #ifdef GSSAPI 700 static int 701 userauth_gssapi(struct ssh *ssh) 702 { 703 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 704 Gssctxt *gssctxt = NULL; 705 OM_uint32 min; 706 int r, ok = 0; 707 gss_OID mech = NULL; 708 709 /* Try one GSSAPI method at a time, rather than sending them all at 710 * once. */ 711 712 if (authctxt->gss_supported_mechs == NULL) 713 gss_indicate_mechs(&min, &authctxt->gss_supported_mechs); 714 715 /* Check to see whether the mechanism is usable before we offer it */ 716 while (authctxt->mech_tried < authctxt->gss_supported_mechs->count && 717 !ok) { 718 mech = &authctxt->gss_supported_mechs-> 719 elements[authctxt->mech_tried]; 720 /* My DER encoding requires length<128 */ 721 if (mech->length < 128 && ssh_gssapi_check_mechanism(&gssctxt, 722 mech, authctxt->host)) { 723 ok = 1; /* Mechanism works */ 724 } else { 725 authctxt->mech_tried++; 726 } 727 } 728 729 if (!ok || mech == NULL) 730 return 0; 731 732 authctxt->methoddata=(void *)gssctxt; 733 734 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 735 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 736 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 737 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 738 (r = sshpkt_put_u32(ssh, 1)) != 0 || 739 (r = sshpkt_put_u32(ssh, (mech->length) + 2)) != 0 || 740 (r = sshpkt_put_u8(ssh, SSH_GSS_OIDTYPE)) != 0 || 741 (r = sshpkt_put_u8(ssh, mech->length)) != 0 || 742 (r = sshpkt_put(ssh, mech->elements, mech->length)) != 0 || 743 (r = sshpkt_send(ssh)) != 0) 744 fatal("%s: %s", __func__, ssh_err(r)); 745 746 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 747 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 748 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 749 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 750 751 authctxt->mech_tried++; /* Move along to next candidate */ 752 753 return 1; 754 } 755 756 static void 757 userauth_gssapi_cleanup(struct ssh *ssh) 758 { 759 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 760 Gssctxt *gssctxt = (Gssctxt *)authctxt->methoddata; 761 762 ssh_gssapi_delete_ctx(&gssctxt); 763 authctxt->methoddata = NULL; 764 765 free(authctxt->gss_supported_mechs); 766 authctxt->gss_supported_mechs = NULL; 767 } 768 769 static OM_uint32 770 process_gssapi_token(struct ssh *ssh, gss_buffer_t recv_tok) 771 { 772 Authctxt *authctxt = ssh->authctxt; 773 Gssctxt *gssctxt = authctxt->methoddata; 774 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 775 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 776 gss_buffer_desc gssbuf; 777 OM_uint32 status, ms, flags; 778 int r; 779 780 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 781 recv_tok, &send_tok, &flags); 782 783 if (send_tok.length > 0) { 784 u_char type = GSS_ERROR(status) ? 785 SSH2_MSG_USERAUTH_GSSAPI_ERRTOK : 786 SSH2_MSG_USERAUTH_GSSAPI_TOKEN; 787 788 if ((r = sshpkt_start(ssh, type)) != 0 || 789 (r = sshpkt_put_string(ssh, send_tok.value, 790 send_tok.length)) != 0 || 791 (r = sshpkt_send(ssh)) != 0) 792 fatal("%s: %s", __func__, ssh_err(r)); 793 794 gss_release_buffer(&ms, &send_tok); 795 } 796 797 if (status == GSS_S_COMPLETE) { 798 /* send either complete or MIC, depending on mechanism */ 799 if (!(flags & GSS_C_INTEG_FLAG)) { 800 if ((r = sshpkt_start(ssh, 801 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE)) != 0 || 802 (r = sshpkt_send(ssh)) != 0) 803 fatal("%s: %s", __func__, ssh_err(r)); 804 } else { 805 struct sshbuf *b; 806 807 if ((b = sshbuf_new()) == NULL) 808 fatal("%s: sshbuf_new failed", __func__); 809 ssh_gssapi_buildmic(b, authctxt->server_user, 810 authctxt->service, "gssapi-with-mic"); 811 812 if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL) 813 fatal("%s: sshbuf_mutable_ptr failed", __func__); 814 gssbuf.length = sshbuf_len(b); 815 816 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 817 818 if (!GSS_ERROR(status)) { 819 if ((r = sshpkt_start(ssh, 820 SSH2_MSG_USERAUTH_GSSAPI_MIC)) != 0 || 821 (r = sshpkt_put_string(ssh, mic.value, 822 mic.length)) != 0 || 823 (r = sshpkt_send(ssh)) != 0) 824 fatal("%s: %s", __func__, ssh_err(r)); 825 } 826 827 sshbuf_free(b); 828 gss_release_buffer(&ms, &mic); 829 } 830 } 831 832 return status; 833 } 834 835 /* ARGSUSED */ 836 static int 837 input_gssapi_response(int type, u_int32_t plen, struct ssh *ssh) 838 { 839 Authctxt *authctxt = ssh->authctxt; 840 Gssctxt *gssctxt; 841 size_t oidlen; 842 u_char *oidv = NULL; 843 int r; 844 845 if (authctxt == NULL) 846 fatal("input_gssapi_response: no authentication context"); 847 gssctxt = authctxt->methoddata; 848 849 /* Setup our OID */ 850 if ((r = sshpkt_get_string(ssh, &oidv, &oidlen)) != 0) 851 goto done; 852 853 if (oidlen <= 2 || 854 oidv[0] != SSH_GSS_OIDTYPE || 855 oidv[1] != oidlen - 2) { 856 debug("Badly encoded mechanism OID received"); 857 userauth(ssh, NULL); 858 goto ok; 859 } 860 861 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 862 fatal("Server returned different OID than expected"); 863 864 if ((r = sshpkt_get_end(ssh)) != 0) 865 goto done; 866 867 if (GSS_ERROR(process_gssapi_token(ssh, GSS_C_NO_BUFFER))) { 868 /* Start again with next method on list */ 869 debug("Trying to start again"); 870 userauth(ssh, NULL); 871 goto ok; 872 } 873 ok: 874 r = 0; 875 done: 876 free(oidv); 877 return r; 878 } 879 880 /* ARGSUSED */ 881 static int 882 input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh) 883 { 884 Authctxt *authctxt = ssh->authctxt; 885 gss_buffer_desc recv_tok; 886 u_char *p = NULL; 887 size_t len; 888 OM_uint32 status; 889 int r; 890 891 if (authctxt == NULL) 892 fatal("input_gssapi_response: no authentication context"); 893 894 if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || 895 (r = sshpkt_get_end(ssh)) != 0) 896 goto out; 897 898 recv_tok.value = p; 899 recv_tok.length = len; 900 status = process_gssapi_token(ssh, &recv_tok); 901 902 /* Start again with the next method in the list */ 903 if (GSS_ERROR(status)) { 904 userauth(ssh, NULL); 905 /* ok */ 906 } 907 r = 0; 908 out: 909 free(p); 910 return r; 911 } 912 913 /* ARGSUSED */ 914 static int 915 input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh) 916 { 917 Authctxt *authctxt = ssh->authctxt; 918 Gssctxt *gssctxt; 919 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 920 gss_buffer_desc recv_tok; 921 OM_uint32 ms; 922 u_char *p = NULL; 923 size_t len; 924 int r; 925 926 if (authctxt == NULL) 927 fatal("input_gssapi_response: no authentication context"); 928 gssctxt = authctxt->methoddata; 929 930 if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || 931 (r = sshpkt_get_end(ssh)) != 0) { 932 free(p); 933 return r; 934 } 935 936 /* Stick it into GSSAPI and see what it says */ 937 recv_tok.value = p; 938 recv_tok.length = len; 939 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 940 &recv_tok, &send_tok, NULL); 941 free(p); 942 gss_release_buffer(&ms, &send_tok); 943 944 /* Server will be returning a failed packet after this one */ 945 return 0; 946 } 947 948 /* ARGSUSED */ 949 static int 950 input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh) 951 { 952 char *msg = NULL; 953 char *lang = NULL; 954 int r; 955 956 if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* maj */ 957 (r = sshpkt_get_u32(ssh, NULL)) != 0 || /* min */ 958 (r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 959 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 960 goto out; 961 r = sshpkt_get_end(ssh); 962 debug("Server GSSAPI Error:\n%s", msg); 963 out: 964 free(msg); 965 free(lang); 966 return r; 967 } 968 #endif /* GSSAPI */ 969 970 static int 971 userauth_none(struct ssh *ssh) 972 { 973 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 974 int r; 975 976 /* initial userauth request */ 977 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 978 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 979 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 980 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 981 (r = sshpkt_send(ssh)) != 0) 982 fatal("%s: %s", __func__, ssh_err(r)); 983 return 1; 984 } 985 986 static int 987 userauth_passwd(struct ssh *ssh) 988 { 989 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 990 char *password, *prompt = NULL; 991 const char *host = options.host_key_alias ? options.host_key_alias : 992 authctxt->host; 993 int r; 994 995 if (authctxt->attempt_passwd++ >= options.number_of_password_prompts) 996 return 0; 997 998 if (authctxt->attempt_passwd != 1) 999 error("Permission denied, please try again."); 1000 1001 xasprintf(&prompt, "%s@%s's password: ", authctxt->server_user, host); 1002 password = read_passphrase(prompt, 0); 1003 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1004 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1005 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1006 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1007 (r = sshpkt_put_u8(ssh, 0)) != 0 || 1008 (r = sshpkt_put_cstring(ssh, password)) != 0 || 1009 (r = sshpkt_add_padding(ssh, 64)) != 0 || 1010 (r = sshpkt_send(ssh)) != 0) 1011 fatal("%s: %s", __func__, ssh_err(r)); 1012 1013 free(prompt); 1014 if (password != NULL) 1015 freezero(password, strlen(password)); 1016 1017 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1018 &input_userauth_passwd_changereq); 1019 1020 return 1; 1021 } 1022 1023 /* 1024 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 1025 */ 1026 /* ARGSUSED */ 1027 static int 1028 input_userauth_passwd_changereq(int type, u_int32_t seqnr, struct ssh *ssh) 1029 { 1030 Authctxt *authctxt = ssh->authctxt; 1031 char *info = NULL, *lang = NULL, *password = NULL, *retype = NULL; 1032 char prompt[256]; 1033 const char *host; 1034 int r; 1035 1036 debug2("input_userauth_passwd_changereq"); 1037 1038 if (authctxt == NULL) 1039 fatal("input_userauth_passwd_changereq: " 1040 "no authentication context"); 1041 host = options.host_key_alias ? options.host_key_alias : authctxt->host; 1042 1043 if ((r = sshpkt_get_cstring(ssh, &info, NULL)) != 0 || 1044 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 1045 goto out; 1046 if (strlen(info) > 0) 1047 logit("%s", info); 1048 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1049 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1050 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1051 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1052 (r = sshpkt_put_u8(ssh, 1)) != 0) /* additional info */ 1053 goto out; 1054 1055 snprintf(prompt, sizeof(prompt), 1056 "Enter %.30s@%.128s's old password: ", 1057 authctxt->server_user, host); 1058 password = read_passphrase(prompt, 0); 1059 if ((r = sshpkt_put_cstring(ssh, password)) != 0) 1060 goto out; 1061 1062 freezero(password, strlen(password)); 1063 password = NULL; 1064 while (password == NULL) { 1065 snprintf(prompt, sizeof(prompt), 1066 "Enter %.30s@%.128s's new password: ", 1067 authctxt->server_user, host); 1068 password = read_passphrase(prompt, RP_ALLOW_EOF); 1069 if (password == NULL) { 1070 /* bail out */ 1071 r = 0; 1072 goto out; 1073 } 1074 snprintf(prompt, sizeof(prompt), 1075 "Retype %.30s@%.128s's new password: ", 1076 authctxt->server_user, host); 1077 retype = read_passphrase(prompt, 0); 1078 if (strcmp(password, retype) != 0) { 1079 freezero(password, strlen(password)); 1080 logit("Mismatch; try again, EOF to quit."); 1081 password = NULL; 1082 } 1083 freezero(retype, strlen(retype)); 1084 } 1085 if ((r = sshpkt_put_cstring(ssh, password)) != 0 || 1086 (r = sshpkt_add_padding(ssh, 64)) != 0 || 1087 (r = sshpkt_send(ssh)) != 0) 1088 goto out; 1089 1090 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1091 &input_userauth_passwd_changereq); 1092 r = 0; 1093 out: 1094 if (password) 1095 freezero(password, strlen(password)); 1096 free(info); 1097 free(lang); 1098 return r; 1099 } 1100 1101 /* 1102 * Select an algorithm for publickey signatures. 1103 * Returns algorithm (caller must free) or NULL if no mutual algorithm found. 1104 * 1105 * Call with ssh==NULL to ignore server-sig-algs extension list and 1106 * only attempt with the key's base signature type. 1107 */ 1108 static char * 1109 key_sig_algorithm(struct ssh *ssh, const struct sshkey *key) 1110 { 1111 char *allowed, *oallowed, *cp, *tmp, *alg = NULL; 1112 1113 /* 1114 * The signature algorithm will only differ from the key algorithm 1115 * for RSA keys/certs and when the server advertises support for 1116 * newer (SHA2) algorithms. 1117 */ 1118 if (ssh == NULL || ssh->kex->server_sig_algs == NULL || 1119 (key->type != KEY_RSA && key->type != KEY_RSA_CERT) || 1120 (key->type == KEY_RSA_CERT && (datafellows & SSH_BUG_SIGTYPE))) { 1121 /* Filter base key signature alg against our configuration */ 1122 return match_list(sshkey_ssh_name(key), 1123 options.pubkey_key_types, NULL); 1124 } 1125 1126 /* 1127 * For RSA keys/certs, since these might have a different sig type: 1128 * find the first entry in PubkeyAcceptedKeyTypes of the right type 1129 * that also appears in the supported signature algorithms list from 1130 * the server. 1131 */ 1132 oallowed = allowed = xstrdup(options.pubkey_key_types); 1133 while ((cp = strsep(&allowed, ",")) != NULL) { 1134 if (sshkey_type_from_name(cp) != key->type) 1135 continue; 1136 tmp = match_list(sshkey_sigalg_by_name(cp), ssh->kex->server_sig_algs, NULL); 1137 if (tmp != NULL) 1138 alg = xstrdup(cp); 1139 free(tmp); 1140 if (alg != NULL) 1141 break; 1142 } 1143 free(oallowed); 1144 return alg; 1145 } 1146 1147 static int 1148 identity_sign(struct identity *id, u_char **sigp, size_t *lenp, 1149 const u_char *data, size_t datalen, u_int compat, const char *alg) 1150 { 1151 struct sshkey *sign_key = NULL, *prv = NULL; 1152 int r = SSH_ERR_INTERNAL_ERROR; 1153 struct notifier_ctx *notifier = NULL; 1154 char *fp = NULL; 1155 1156 *sigp = NULL; 1157 *lenp = 0; 1158 1159 /* The agent supports this key. */ 1160 if (id->key != NULL && id->agent_fd != -1) { 1161 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, 1162 data, datalen, alg, compat); 1163 } 1164 1165 /* 1166 * We have already loaded the private key or the private key is 1167 * stored in external hardware. 1168 */ 1169 if (id->key != NULL && 1170 (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))) { 1171 sign_key = id->key; 1172 } else { 1173 /* Load the private key from the file. */ 1174 if ((prv = load_identity_file(id)) == NULL) 1175 return SSH_ERR_KEY_NOT_FOUND; 1176 if (id->key != NULL && !sshkey_equal_public(prv, id->key)) { 1177 error("%s: private key %s contents do not match public", 1178 __func__, id->filename); 1179 r = SSH_ERR_KEY_NOT_FOUND; 1180 goto out; 1181 } 1182 sign_key = prv; 1183 if (sshkey_is_sk(sign_key) && 1184 (sign_key->sk_flags & SSH_SK_USER_PRESENCE_REQD)) { 1185 /* XXX match batch mode should just skip these keys? */ 1186 if ((fp = sshkey_fingerprint(sign_key, 1187 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1188 fatal("%s: sshkey_fingerprint", __func__); 1189 notifier = notify_start(options.batch_mode, 1190 "Confirm user presence for key %s %s", 1191 sshkey_type(sign_key), fp); 1192 free(fp); 1193 } 1194 } 1195 if ((r = sshkey_sign(sign_key, sigp, lenp, data, datalen, 1196 alg, options.sk_provider, compat)) != 0) { 1197 debug("%s: sshkey_sign: %s", __func__, ssh_err(r)); 1198 goto out; 1199 } 1200 /* 1201 * PKCS#11 tokens may not support all signature algorithms, 1202 * so check what we get back. 1203 */ 1204 if ((r = sshkey_check_sigtype(*sigp, *lenp, alg)) != 0) { 1205 debug("%s: sshkey_check_sigtype: %s", __func__, ssh_err(r)); 1206 goto out; 1207 } 1208 /* success */ 1209 r = 0; 1210 out: 1211 notify_complete(notifier); 1212 sshkey_free(prv); 1213 return r; 1214 } 1215 1216 static int 1217 id_filename_matches(Identity *id, Identity *private_id) 1218 { 1219 const char *suffixes[] = { ".pub", "-cert.pub", NULL }; 1220 size_t len = strlen(id->filename), plen = strlen(private_id->filename); 1221 size_t i, slen; 1222 1223 if (strcmp(id->filename, private_id->filename) == 0) 1224 return 1; 1225 for (i = 0; suffixes[i]; i++) { 1226 slen = strlen(suffixes[i]); 1227 if (len > slen && plen == len - slen && 1228 strcmp(id->filename + (len - slen), suffixes[i]) == 0 && 1229 memcmp(id->filename, private_id->filename, plen) == 0) 1230 return 1; 1231 } 1232 return 0; 1233 } 1234 1235 static int 1236 sign_and_send_pubkey(struct ssh *ssh, Identity *id) 1237 { 1238 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1239 struct sshbuf *b = NULL; 1240 Identity *private_id, *sign_id = NULL; 1241 u_char *signature = NULL; 1242 size_t slen = 0, skip = 0; 1243 int r, fallback_sigtype, sent = 0; 1244 char *alg = NULL, *fp = NULL; 1245 const char *loc = ""; 1246 1247 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 1248 SSH_FP_DEFAULT)) == NULL) 1249 return 0; 1250 1251 debug3("%s: %s %s", __func__, sshkey_type(id->key), fp); 1252 1253 /* 1254 * If the key is an certificate, try to find a matching private key 1255 * and use it to complete the signature. 1256 * If no such private key exists, fall back to trying the certificate 1257 * key itself in case it has a private half already loaded. 1258 * This will try to set sign_id to the private key that will perform 1259 * the signature. 1260 */ 1261 if (sshkey_is_cert(id->key)) { 1262 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1263 if (sshkey_equal_public(id->key, private_id->key) && 1264 id->key->type != private_id->key->type) { 1265 sign_id = private_id; 1266 break; 1267 } 1268 } 1269 /* 1270 * Exact key matches are preferred, but also allow 1271 * filename matches for non-PKCS#11/agent keys that 1272 * didn't load public keys. This supports the case 1273 * of keeping just a private key file and public 1274 * certificate on disk. 1275 */ 1276 if (sign_id == NULL && 1277 !id->isprivate && id->agent_fd == -1 && 1278 (id->key->flags & SSHKEY_FLAG_EXT) == 0) { 1279 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1280 if (private_id->key == NULL && 1281 id_filename_matches(id, private_id)) { 1282 sign_id = private_id; 1283 break; 1284 } 1285 } 1286 } 1287 if (sign_id != NULL) { 1288 debug2("%s: using private key \"%s\"%s for " 1289 "certificate", __func__, id->filename, 1290 id->agent_fd != -1 ? " from agent" : ""); 1291 } else { 1292 debug("%s: no separate private key for certificate " 1293 "\"%s\"", __func__, id->filename); 1294 } 1295 } 1296 1297 /* 1298 * If the above didn't select another identity to do the signing 1299 * then default to the one we started with. 1300 */ 1301 if (sign_id == NULL) 1302 sign_id = id; 1303 1304 /* assemble and sign data */ 1305 for (fallback_sigtype = 0; fallback_sigtype <= 1; fallback_sigtype++) { 1306 free(alg); 1307 slen = 0; 1308 signature = NULL; 1309 if ((alg = key_sig_algorithm(fallback_sigtype ? NULL : ssh, 1310 id->key)) == NULL) { 1311 error("%s: no mutual signature supported", __func__); 1312 goto out; 1313 } 1314 debug3("%s: signing using %s %s", __func__, alg, fp); 1315 1316 sshbuf_free(b); 1317 if ((b = sshbuf_new()) == NULL) 1318 fatal("%s: sshbuf_new failed", __func__); 1319 if (datafellows & SSH_OLD_SESSIONID) { 1320 if ((r = sshbuf_put(b, session_id2, 1321 session_id2_len)) != 0) { 1322 fatal("%s: sshbuf_put: %s", 1323 __func__, ssh_err(r)); 1324 } 1325 } else { 1326 if ((r = sshbuf_put_string(b, session_id2, 1327 session_id2_len)) != 0) { 1328 fatal("%s: sshbuf_put_string: %s", 1329 __func__, ssh_err(r)); 1330 } 1331 } 1332 skip = sshbuf_len(b); 1333 if ((r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1334 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 1335 (r = sshbuf_put_cstring(b, authctxt->service)) != 0 || 1336 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 1337 (r = sshbuf_put_u8(b, 1)) != 0 || 1338 (r = sshbuf_put_cstring(b, alg)) != 0 || 1339 (r = sshkey_puts(id->key, b)) != 0) { 1340 fatal("%s: assemble signed data: %s", 1341 __func__, ssh_err(r)); 1342 } 1343 1344 /* generate signature */ 1345 r = identity_sign(sign_id, &signature, &slen, 1346 sshbuf_ptr(b), sshbuf_len(b), datafellows, alg); 1347 if (r == 0) 1348 break; 1349 else if (r == SSH_ERR_KEY_NOT_FOUND) 1350 goto out; /* soft failure */ 1351 else if (r == SSH_ERR_SIGN_ALG_UNSUPPORTED && 1352 !fallback_sigtype) { 1353 if (sign_id->agent_fd != -1) 1354 loc = "agent "; 1355 else if ((sign_id->key->flags & SSHKEY_FLAG_EXT) != 0) 1356 loc = "token "; 1357 logit("%skey %s %s returned incorrect signature type", 1358 loc, sshkey_type(id->key), fp); 1359 continue; 1360 } 1361 error("%s: signing failed for %s \"%s\"%s: %s", __func__, 1362 sshkey_type(sign_id->key), sign_id->filename, 1363 id->agent_fd != -1 ? " from agent" : "", ssh_err(r)); 1364 goto out; 1365 } 1366 if (slen == 0 || signature == NULL) /* shouldn't happen */ 1367 fatal("%s: no signature", __func__); 1368 1369 /* append signature */ 1370 if ((r = sshbuf_put_string(b, signature, slen)) != 0) 1371 fatal("%s: append signature: %s", __func__, ssh_err(r)); 1372 1373 #ifdef DEBUG_PK 1374 sshbuf_dump(b, stderr); 1375 #endif 1376 /* skip session id and packet type */ 1377 if ((r = sshbuf_consume(b, skip + 1)) != 0) 1378 fatal("%s: consume: %s", __func__, ssh_err(r)); 1379 1380 /* put remaining data from buffer into packet */ 1381 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1382 (r = sshpkt_putb(ssh, b)) != 0 || 1383 (r = sshpkt_send(ssh)) != 0) 1384 fatal("%s: enqueue request: %s", __func__, ssh_err(r)); 1385 1386 /* success */ 1387 sent = 1; 1388 1389 out: 1390 free(fp); 1391 free(alg); 1392 sshbuf_free(b); 1393 freezero(signature, slen); 1394 return sent; 1395 } 1396 1397 static int 1398 send_pubkey_test(struct ssh *ssh, Identity *id) 1399 { 1400 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1401 u_char *blob = NULL; 1402 char *alg = NULL; 1403 size_t bloblen; 1404 u_int have_sig = 0; 1405 int sent = 0, r; 1406 1407 if ((alg = key_sig_algorithm(ssh, id->key)) == NULL) { 1408 debug("%s: no mutual signature algorithm", __func__); 1409 goto out; 1410 } 1411 1412 if ((r = sshkey_to_blob(id->key, &blob, &bloblen)) != 0) { 1413 /* we cannot handle this key */ 1414 debug3("%s: cannot handle key", __func__); 1415 goto out; 1416 } 1417 /* register callback for USERAUTH_PK_OK message */ 1418 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1419 1420 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1421 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1422 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1423 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1424 (r = sshpkt_put_u8(ssh, have_sig)) != 0 || 1425 (r = sshpkt_put_cstring(ssh, alg)) != 0 || 1426 (r = sshpkt_put_string(ssh, blob, bloblen)) != 0 || 1427 (r = sshpkt_send(ssh)) != 0) 1428 fatal("%s: %s", __func__, ssh_err(r)); 1429 sent = 1; 1430 1431 out: 1432 free(alg); 1433 free(blob); 1434 return sent; 1435 } 1436 1437 static struct sshkey * 1438 load_identity_file(Identity *id) 1439 { 1440 struct sshkey *private = NULL; 1441 char prompt[300], *passphrase, *comment; 1442 int r, quit = 0, i; 1443 struct stat st; 1444 1445 if (stat(id->filename, &st) == -1) { 1446 (id->userprovided ? logit : debug3)("no such identity: %s: %s", 1447 id->filename, strerror(errno)); 1448 return NULL; 1449 } 1450 snprintf(prompt, sizeof prompt, 1451 "Enter passphrase for key '%.100s': ", id->filename); 1452 for (i = 0; i <= options.number_of_password_prompts; i++) { 1453 if (i == 0) 1454 passphrase = ""; 1455 else { 1456 passphrase = read_passphrase(prompt, 0); 1457 if (*passphrase == '\0') { 1458 debug2("no passphrase given, try next key"); 1459 free(passphrase); 1460 break; 1461 } 1462 } 1463 switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename, 1464 passphrase, &private, &comment))) { 1465 case 0: 1466 break; 1467 case SSH_ERR_KEY_WRONG_PASSPHRASE: 1468 if (options.batch_mode) { 1469 quit = 1; 1470 break; 1471 } 1472 if (i != 0) 1473 debug2("bad passphrase given, try again..."); 1474 break; 1475 case SSH_ERR_SYSTEM_ERROR: 1476 if (errno == ENOENT) { 1477 debug2("Load key \"%s\": %s", 1478 id->filename, ssh_err(r)); 1479 quit = 1; 1480 break; 1481 } 1482 /* FALLTHROUGH */ 1483 default: 1484 error("Load key \"%s\": %s", id->filename, ssh_err(r)); 1485 quit = 1; 1486 break; 1487 } 1488 if (private != NULL && sshkey_is_sk(private) && 1489 options.sk_provider == NULL) { 1490 debug("key \"%s\" is an authenticator-hosted key, " 1491 "but no provider specified", id->filename); 1492 sshkey_free(private); 1493 private = NULL; 1494 quit = 1; 1495 } 1496 if (!quit && private != NULL && id->agent_fd == -1 && 1497 !(id->key && id->isprivate)) 1498 maybe_add_key_to_agent(id->filename, private, comment, 1499 passphrase); 1500 if (i > 0) 1501 freezero(passphrase, strlen(passphrase)); 1502 free(comment); 1503 if (private != NULL || quit) 1504 break; 1505 } 1506 return private; 1507 } 1508 1509 static int 1510 key_type_allowed_by_config(struct sshkey *key) 1511 { 1512 if (match_pattern_list(sshkey_ssh_name(key), 1513 options.pubkey_key_types, 0) == 1) 1514 return 1; 1515 1516 /* RSA keys/certs might be allowed by alternate signature types */ 1517 switch (key->type) { 1518 case KEY_RSA: 1519 if (match_pattern_list("rsa-sha2-512", 1520 options.pubkey_key_types, 0) == 1) 1521 return 1; 1522 if (match_pattern_list("rsa-sha2-256", 1523 options.pubkey_key_types, 0) == 1) 1524 return 1; 1525 break; 1526 case KEY_RSA_CERT: 1527 if (match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", 1528 options.pubkey_key_types, 0) == 1) 1529 return 1; 1530 if (match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", 1531 options.pubkey_key_types, 0) == 1) 1532 return 1; 1533 break; 1534 } 1535 return 0; 1536 } 1537 1538 1539 /* 1540 * try keys in the following order: 1541 * 1. certificates listed in the config file 1542 * 2. other input certificates 1543 * 3. agent keys that are found in the config file 1544 * 4. other agent keys 1545 * 5. keys that are only listed in the config file 1546 */ 1547 static void 1548 pubkey_prepare(Authctxt *authctxt) 1549 { 1550 struct identity *id, *id2, *tmp; 1551 struct idlist agent, files, *preferred; 1552 struct sshkey *key; 1553 int agent_fd = -1, i, r, found; 1554 size_t j; 1555 struct ssh_identitylist *idlist; 1556 char *ident; 1557 1558 TAILQ_INIT(&agent); /* keys from the agent */ 1559 TAILQ_INIT(&files); /* keys from the config file */ 1560 preferred = &authctxt->keys; 1561 TAILQ_INIT(preferred); /* preferred order of keys */ 1562 1563 /* list of keys stored in the filesystem and PKCS#11 */ 1564 for (i = 0; i < options.num_identity_files; i++) { 1565 key = options.identity_keys[i]; 1566 if (key && key->cert && 1567 key->cert->type != SSH2_CERT_TYPE_USER) { 1568 debug("%s: ignoring certificate %s: not a user " 1569 "certificate", __func__, 1570 options.identity_files[i]); 1571 continue; 1572 } 1573 if (key && sshkey_is_sk(key) && options.sk_provider == NULL) { 1574 debug("%s: ignoring authenticator-hosted key %s as no " 1575 "SecurityKeyProvider has been specified", 1576 __func__, options.identity_files[i]); 1577 continue; 1578 } 1579 options.identity_keys[i] = NULL; 1580 id = xcalloc(1, sizeof(*id)); 1581 id->agent_fd = -1; 1582 id->key = key; 1583 id->filename = xstrdup(options.identity_files[i]); 1584 id->userprovided = options.identity_file_userprovided[i]; 1585 TAILQ_INSERT_TAIL(&files, id, next); 1586 } 1587 /* list of certificates specified by user */ 1588 for (i = 0; i < options.num_certificate_files; i++) { 1589 key = options.certificates[i]; 1590 if (!sshkey_is_cert(key) || key->cert == NULL || 1591 key->cert->type != SSH2_CERT_TYPE_USER) { 1592 debug("%s: ignoring certificate %s: not a user " 1593 "certificate", __func__, 1594 options.identity_files[i]); 1595 continue; 1596 } 1597 if (key && sshkey_is_sk(key) && options.sk_provider == NULL) { 1598 debug("%s: ignoring authenticator-hosted key " 1599 "certificate %s as no " 1600 "SecurityKeyProvider has been specified", 1601 __func__, options.identity_files[i]); 1602 continue; 1603 } 1604 id = xcalloc(1, sizeof(*id)); 1605 id->agent_fd = -1; 1606 id->key = key; 1607 id->filename = xstrdup(options.certificate_files[i]); 1608 id->userprovided = options.certificate_file_userprovided[i]; 1609 TAILQ_INSERT_TAIL(preferred, id, next); 1610 } 1611 /* list of keys supported by the agent */ 1612 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { 1613 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1614 debug("%s: ssh_get_authentication_socket: %s", 1615 __func__, ssh_err(r)); 1616 } else if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 1617 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 1618 debug("%s: ssh_fetch_identitylist: %s", 1619 __func__, ssh_err(r)); 1620 close(agent_fd); 1621 } else { 1622 for (j = 0; j < idlist->nkeys; j++) { 1623 found = 0; 1624 TAILQ_FOREACH(id, &files, next) { 1625 /* 1626 * agent keys from the config file are 1627 * preferred 1628 */ 1629 if (sshkey_equal(idlist->keys[j], id->key)) { 1630 TAILQ_REMOVE(&files, id, next); 1631 TAILQ_INSERT_TAIL(preferred, id, next); 1632 id->agent_fd = agent_fd; 1633 found = 1; 1634 break; 1635 } 1636 } 1637 if (!found && !options.identities_only) { 1638 id = xcalloc(1, sizeof(*id)); 1639 /* XXX "steals" key/comment from idlist */ 1640 id->key = idlist->keys[j]; 1641 id->filename = idlist->comments[j]; 1642 idlist->keys[j] = NULL; 1643 idlist->comments[j] = NULL; 1644 id->agent_fd = agent_fd; 1645 TAILQ_INSERT_TAIL(&agent, id, next); 1646 } 1647 } 1648 ssh_free_identitylist(idlist); 1649 /* append remaining agent keys */ 1650 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1651 TAILQ_REMOVE(&agent, id, next); 1652 TAILQ_INSERT_TAIL(preferred, id, next); 1653 } 1654 authctxt->agent_fd = agent_fd; 1655 } 1656 /* Prefer PKCS11 keys that are explicitly listed */ 1657 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1658 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) 1659 continue; 1660 found = 0; 1661 TAILQ_FOREACH(id2, &files, next) { 1662 if (id2->key == NULL || 1663 (id2->key->flags & SSHKEY_FLAG_EXT) == 0) 1664 continue; 1665 if (sshkey_equal(id->key, id2->key)) { 1666 TAILQ_REMOVE(&files, id, next); 1667 TAILQ_INSERT_TAIL(preferred, id, next); 1668 found = 1; 1669 break; 1670 } 1671 } 1672 /* If IdentitiesOnly set and key not found then don't use it */ 1673 if (!found && options.identities_only) { 1674 TAILQ_REMOVE(&files, id, next); 1675 freezero(id, sizeof(*id)); 1676 } 1677 } 1678 /* append remaining keys from the config file */ 1679 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1680 TAILQ_REMOVE(&files, id, next); 1681 TAILQ_INSERT_TAIL(preferred, id, next); 1682 } 1683 /* finally, filter by PubkeyAcceptedKeyTypes */ 1684 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1685 if (id->key != NULL && !key_type_allowed_by_config(id->key)) { 1686 debug("Skipping %s key %s - " 1687 "not in PubkeyAcceptedKeyTypes", 1688 sshkey_ssh_name(id->key), id->filename); 1689 TAILQ_REMOVE(preferred, id, next); 1690 sshkey_free(id->key); 1691 free(id->filename); 1692 memset(id, 0, sizeof(*id)); 1693 continue; 1694 } 1695 } 1696 /* List the keys we plan on using */ 1697 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1698 ident = format_identity(id); 1699 debug("Will attempt key: %s", ident); 1700 free(ident); 1701 } 1702 debug2("%s: done", __func__); 1703 } 1704 1705 static void 1706 pubkey_cleanup(struct ssh *ssh) 1707 { 1708 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1709 Identity *id; 1710 1711 if (authctxt->agent_fd != -1) { 1712 ssh_close_authentication_socket(authctxt->agent_fd); 1713 authctxt->agent_fd = -1; 1714 } 1715 for (id = TAILQ_FIRST(&authctxt->keys); id; 1716 id = TAILQ_FIRST(&authctxt->keys)) { 1717 TAILQ_REMOVE(&authctxt->keys, id, next); 1718 sshkey_free(id->key); 1719 free(id->filename); 1720 free(id); 1721 } 1722 } 1723 1724 static void 1725 pubkey_reset(Authctxt *authctxt) 1726 { 1727 Identity *id; 1728 1729 TAILQ_FOREACH(id, &authctxt->keys, next) 1730 id->tried = 0; 1731 } 1732 1733 static int 1734 try_identity(Identity *id) 1735 { 1736 if (!id->key) 1737 return (0); 1738 if (sshkey_type_plain(id->key->type) == KEY_RSA && 1739 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1740 debug("Skipped %s key %s for RSA/MD5 server", 1741 sshkey_type(id->key), id->filename); 1742 return (0); 1743 } 1744 return 1; 1745 } 1746 1747 static int 1748 userauth_pubkey(struct ssh *ssh) 1749 { 1750 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1751 Identity *id; 1752 int sent = 0; 1753 char *ident; 1754 1755 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1756 if (id->tried++) 1757 return (0); 1758 /* move key to the end of the queue */ 1759 TAILQ_REMOVE(&authctxt->keys, id, next); 1760 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1761 /* 1762 * send a test message if we have the public key. for 1763 * encrypted keys we cannot do this and have to load the 1764 * private key instead 1765 */ 1766 if (id->key != NULL) { 1767 if (try_identity(id)) { 1768 ident = format_identity(id); 1769 debug("Offering public key: %s", ident); 1770 free(ident); 1771 sent = send_pubkey_test(ssh, id); 1772 } 1773 } else { 1774 debug("Trying private key: %s", id->filename); 1775 id->key = load_identity_file(id); 1776 if (id->key != NULL) { 1777 if (try_identity(id)) { 1778 id->isprivate = 1; 1779 sent = sign_and_send_pubkey(ssh, id); 1780 } 1781 sshkey_free(id->key); 1782 id->key = NULL; 1783 id->isprivate = 0; 1784 } 1785 } 1786 if (sent) 1787 return (sent); 1788 } 1789 return (0); 1790 } 1791 1792 /* 1793 * Send userauth request message specifying keyboard-interactive method. 1794 */ 1795 static int 1796 userauth_kbdint(struct ssh *ssh) 1797 { 1798 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1799 int r; 1800 1801 if (authctxt->attempt_kbdint++ >= options.number_of_password_prompts) 1802 return 0; 1803 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1804 if (authctxt->attempt_kbdint > 1 && !authctxt->info_req_seen) { 1805 debug3("userauth_kbdint: disable: no info_req_seen"); 1806 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1807 return 0; 1808 } 1809 1810 debug2("userauth_kbdint"); 1811 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1812 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1813 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1814 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1815 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* lang */ 1816 (r = sshpkt_put_cstring(ssh, options.kbd_interactive_devices ? 1817 options.kbd_interactive_devices : "")) != 0 || 1818 (r = sshpkt_send(ssh)) != 0) 1819 fatal("%s: %s", __func__, ssh_err(r)); 1820 1821 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1822 return 1; 1823 } 1824 1825 /* 1826 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1827 */ 1828 static int 1829 input_userauth_info_req(int type, u_int32_t seq, struct ssh *ssh) 1830 { 1831 Authctxt *authctxt = ssh->authctxt; 1832 char *name = NULL, *inst = NULL, *lang = NULL, *prompt = NULL; 1833 char *response = NULL; 1834 u_char echo = 0; 1835 u_int num_prompts, i; 1836 int r; 1837 1838 debug2("input_userauth_info_req"); 1839 1840 if (authctxt == NULL) 1841 fatal("input_userauth_info_req: no authentication context"); 1842 1843 authctxt->info_req_seen = 1; 1844 1845 if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 || 1846 (r = sshpkt_get_cstring(ssh, &inst, NULL)) != 0 || 1847 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 1848 goto out; 1849 if (strlen(name) > 0) 1850 logit("%s", name); 1851 if (strlen(inst) > 0) 1852 logit("%s", inst); 1853 1854 if ((r = sshpkt_get_u32(ssh, &num_prompts)) != 0) 1855 goto out; 1856 /* 1857 * Begin to build info response packet based on prompts requested. 1858 * We commit to providing the correct number of responses, so if 1859 * further on we run into a problem that prevents this, we have to 1860 * be sure and clean this up and send a correct error response. 1861 */ 1862 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE)) != 0 || 1863 (r = sshpkt_put_u32(ssh, num_prompts)) != 0) 1864 goto out; 1865 1866 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1867 for (i = 0; i < num_prompts; i++) { 1868 if ((r = sshpkt_get_cstring(ssh, &prompt, NULL)) != 0 || 1869 (r = sshpkt_get_u8(ssh, &echo)) != 0) 1870 goto out; 1871 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1872 if ((r = sshpkt_put_cstring(ssh, response)) != 0) 1873 goto out; 1874 freezero(response, strlen(response)); 1875 free(prompt); 1876 response = prompt = NULL; 1877 } 1878 /* done with parsing incoming message. */ 1879 if ((r = sshpkt_get_end(ssh)) != 0 || 1880 (r = sshpkt_add_padding(ssh, 64)) != 0) 1881 goto out; 1882 r = sshpkt_send(ssh); 1883 out: 1884 if (response) 1885 freezero(response, strlen(response)); 1886 free(prompt); 1887 free(name); 1888 free(inst); 1889 free(lang); 1890 return r; 1891 } 1892 1893 static int 1894 ssh_keysign(struct ssh *ssh, struct sshkey *key, u_char **sigp, size_t *lenp, 1895 const u_char *data, size_t datalen) 1896 { 1897 struct sshbuf *b; 1898 struct stat st; 1899 pid_t pid; 1900 int r, to[2], from[2], status; 1901 int sock = ssh_packet_get_connection_in(ssh); 1902 u_char rversion = 0, version = 2; 1903 void (*osigchld)(int); 1904 1905 *sigp = NULL; 1906 *lenp = 0; 1907 1908 if (stat(_PATH_SSH_KEY_SIGN, &st) == -1) { 1909 error("%s: not installed: %s", __func__, strerror(errno)); 1910 return -1; 1911 } 1912 if (fflush(stdout) != 0) { 1913 error("%s: fflush: %s", __func__, strerror(errno)); 1914 return -1; 1915 } 1916 if (pipe(to) == -1) { 1917 error("%s: pipe: %s", __func__, strerror(errno)); 1918 return -1; 1919 } 1920 if (pipe(from) == -1) { 1921 error("%s: pipe: %s", __func__, strerror(errno)); 1922 return -1; 1923 } 1924 if ((pid = fork()) == -1) { 1925 error("%s: fork: %s", __func__, strerror(errno)); 1926 return -1; 1927 } 1928 osigchld = ssh_signal(SIGCHLD, SIG_DFL); 1929 if (pid == 0) { 1930 close(from[0]); 1931 if (dup2(from[1], STDOUT_FILENO) == -1) 1932 fatal("%s: dup2: %s", __func__, strerror(errno)); 1933 close(to[1]); 1934 if (dup2(to[0], STDIN_FILENO) == -1) 1935 fatal("%s: dup2: %s", __func__, strerror(errno)); 1936 close(from[1]); 1937 close(to[0]); 1938 1939 if (dup2(sock, STDERR_FILENO + 1) == -1) 1940 fatal("%s: dup2: %s", __func__, strerror(errno)); 1941 sock = STDERR_FILENO + 1; 1942 fcntl(sock, F_SETFD, 0); /* keep the socket on exec */ 1943 closefrom(sock + 1); 1944 1945 debug3("%s: [child] pid=%ld, exec %s", 1946 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); 1947 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL); 1948 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, 1949 strerror(errno)); 1950 } 1951 close(from[1]); 1952 close(to[0]); 1953 sock = STDERR_FILENO + 1; 1954 1955 if ((b = sshbuf_new()) == NULL) 1956 fatal("%s: sshbuf_new failed", __func__); 1957 /* send # of sock, data to be signed */ 1958 if ((r = sshbuf_put_u32(b, sock)) != 0 || 1959 (r = sshbuf_put_string(b, data, datalen)) != 0) 1960 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1961 if (ssh_msg_send(to[1], version, b) == -1) 1962 fatal("%s: couldn't send request", __func__); 1963 sshbuf_reset(b); 1964 r = ssh_msg_recv(from[0], b); 1965 close(from[0]); 1966 close(to[1]); 1967 if (r < 0) { 1968 error("%s: no reply", __func__); 1969 goto fail; 1970 } 1971 1972 errno = 0; 1973 while (waitpid(pid, &status, 0) == -1) { 1974 if (errno != EINTR) { 1975 error("%s: waitpid %ld: %s", 1976 __func__, (long)pid, strerror(errno)); 1977 goto fail; 1978 } 1979 } 1980 if (!WIFEXITED(status)) { 1981 error("%s: exited abnormally", __func__); 1982 goto fail; 1983 } 1984 if (WEXITSTATUS(status) != 0) { 1985 error("%s: exited with status %d", 1986 __func__, WEXITSTATUS(status)); 1987 goto fail; 1988 } 1989 if ((r = sshbuf_get_u8(b, &rversion)) != 0) { 1990 error("%s: buffer error: %s", __func__, ssh_err(r)); 1991 goto fail; 1992 } 1993 if (rversion != version) { 1994 error("%s: bad version", __func__); 1995 goto fail; 1996 } 1997 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { 1998 error("%s: buffer error: %s", __func__, ssh_err(r)); 1999 fail: 2000 ssh_signal(SIGCHLD, osigchld); 2001 sshbuf_free(b); 2002 return -1; 2003 } 2004 ssh_signal(SIGCHLD, osigchld); 2005 sshbuf_free(b); 2006 2007 return 0; 2008 } 2009 2010 static int 2011 userauth_hostbased(struct ssh *ssh) 2012 { 2013 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 2014 struct sshkey *private = NULL; 2015 struct sshbuf *b = NULL; 2016 u_char *sig = NULL, *keyblob = NULL; 2017 char *fp = NULL, *chost = NULL, *lname = NULL; 2018 size_t siglen = 0, keylen = 0; 2019 int i, r, success = 0; 2020 2021 if (authctxt->ktypes == NULL) { 2022 authctxt->oktypes = xstrdup(options.hostbased_key_types); 2023 authctxt->ktypes = authctxt->oktypes; 2024 } 2025 2026 /* 2027 * Work through each listed type pattern in HostbasedKeyTypes, 2028 * trying each hostkey that matches the type in turn. 2029 */ 2030 for (;;) { 2031 if (authctxt->active_ktype == NULL) 2032 authctxt->active_ktype = strsep(&authctxt->ktypes, ","); 2033 if (authctxt->active_ktype == NULL || 2034 *authctxt->active_ktype == '\0') 2035 break; 2036 debug3("%s: trying key type %s", __func__, 2037 authctxt->active_ktype); 2038 2039 /* check for a useful key */ 2040 private = NULL; 2041 for (i = 0; i < authctxt->sensitive->nkeys; i++) { 2042 if (authctxt->sensitive->keys[i] == NULL || 2043 authctxt->sensitive->keys[i]->type == KEY_UNSPEC) 2044 continue; 2045 if (match_pattern_list( 2046 sshkey_ssh_name(authctxt->sensitive->keys[i]), 2047 authctxt->active_ktype, 0) != 1) 2048 continue; 2049 /* we take and free the key */ 2050 private = authctxt->sensitive->keys[i]; 2051 authctxt->sensitive->keys[i] = NULL; 2052 break; 2053 } 2054 /* Found one */ 2055 if (private != NULL) 2056 break; 2057 /* No more keys of this type; advance */ 2058 authctxt->active_ktype = NULL; 2059 } 2060 if (private == NULL) { 2061 free(authctxt->oktypes); 2062 authctxt->oktypes = authctxt->ktypes = NULL; 2063 authctxt->active_ktype = NULL; 2064 debug("No more client hostkeys for hostbased authentication."); 2065 goto out; 2066 } 2067 2068 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, 2069 SSH_FP_DEFAULT)) == NULL) { 2070 error("%s: sshkey_fingerprint failed", __func__); 2071 goto out; 2072 } 2073 debug("%s: trying hostkey %s %s", 2074 __func__, sshkey_ssh_name(private), fp); 2075 2076 /* figure out a name for the client host */ 2077 lname = get_local_name(ssh_packet_get_connection_in(ssh)); 2078 if (lname == NULL) { 2079 error("%s: cannot get local ipaddr/name", __func__); 2080 goto out; 2081 } 2082 2083 /* XXX sshbuf_put_stringf? */ 2084 xasprintf(&chost, "%s.", lname); 2085 debug2("%s: chost %s", __func__, chost); 2086 2087 /* construct data */ 2088 if ((b = sshbuf_new()) == NULL) { 2089 error("%s: sshbuf_new failed", __func__); 2090 goto out; 2091 } 2092 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { 2093 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 2094 goto out; 2095 } 2096 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || 2097 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 2098 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 2099 (r = sshbuf_put_cstring(b, authctxt->service)) != 0 || 2100 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 2101 (r = sshbuf_put_cstring(b, sshkey_ssh_name(private))) != 0 || 2102 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || 2103 (r = sshbuf_put_cstring(b, chost)) != 0 || 2104 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { 2105 error("%s: buffer error: %s", __func__, ssh_err(r)); 2106 goto out; 2107 } 2108 2109 #ifdef DEBUG_PK 2110 sshbuf_dump(b, stderr); 2111 #endif 2112 if ((r = ssh_keysign(ssh, private, &sig, &siglen, 2113 sshbuf_ptr(b), sshbuf_len(b))) != 0) { 2114 error("sign using hostkey %s %s failed", 2115 sshkey_ssh_name(private), fp); 2116 goto out; 2117 } 2118 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 2119 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 2120 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 2121 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 2122 (r = sshpkt_put_cstring(ssh, sshkey_ssh_name(private))) != 0 || 2123 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || 2124 (r = sshpkt_put_cstring(ssh, chost)) != 0 || 2125 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || 2126 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || 2127 (r = sshpkt_send(ssh)) != 0) { 2128 error("%s: packet error: %s", __func__, ssh_err(r)); 2129 goto out; 2130 } 2131 success = 1; 2132 2133 out: 2134 if (sig != NULL) 2135 freezero(sig, siglen); 2136 free(keyblob); 2137 free(lname); 2138 free(fp); 2139 free(chost); 2140 sshkey_free(private); 2141 sshbuf_free(b); 2142 2143 return success; 2144 } 2145 2146 /* find auth method */ 2147 2148 /* 2149 * given auth method name, if configurable options permit this method fill 2150 * in auth_ident field and return true, otherwise return false. 2151 */ 2152 static int 2153 authmethod_is_enabled(Authmethod *method) 2154 { 2155 if (method == NULL) 2156 return 0; 2157 /* return false if options indicate this method is disabled */ 2158 if (method->enabled == NULL || *method->enabled == 0) 2159 return 0; 2160 /* return false if batch mode is enabled but method needs interactive mode */ 2161 if (method->batch_flag != NULL && *method->batch_flag != 0) 2162 return 0; 2163 return 1; 2164 } 2165 2166 static Authmethod * 2167 authmethod_lookup(const char *name) 2168 { 2169 Authmethod *method = NULL; 2170 if (name != NULL) 2171 for (method = authmethods; method->name != NULL; method++) 2172 if (strcmp(name, method->name) == 0) 2173 return method; 2174 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 2175 return NULL; 2176 } 2177 2178 /* XXX internal state */ 2179 static Authmethod *current = NULL; 2180 static char *supported = NULL; 2181 static char *preferred = NULL; 2182 2183 /* 2184 * Given the authentication method list sent by the server, return the 2185 * next method we should try. If the server initially sends a nil list, 2186 * use a built-in default list. 2187 */ 2188 static Authmethod * 2189 authmethod_get(char *authlist) 2190 { 2191 char *name = NULL; 2192 u_int next; 2193 2194 /* Use a suitable default if we're passed a nil list. */ 2195 if (authlist == NULL || strlen(authlist) == 0) 2196 authlist = options.preferred_authentications; 2197 2198 if (supported == NULL || strcmp(authlist, supported) != 0) { 2199 debug3("start over, passed a different list %s", authlist); 2200 free(supported); 2201 supported = xstrdup(authlist); 2202 preferred = options.preferred_authentications; 2203 debug3("preferred %s", preferred); 2204 current = NULL; 2205 } else if (current != NULL && authmethod_is_enabled(current)) 2206 return current; 2207 2208 for (;;) { 2209 if ((name = match_list(preferred, supported, &next)) == NULL) { 2210 debug("No more authentication methods to try."); 2211 current = NULL; 2212 return NULL; 2213 } 2214 preferred += next; 2215 debug3("authmethod_lookup %s", name); 2216 debug3("remaining preferred: %s", preferred); 2217 if ((current = authmethod_lookup(name)) != NULL && 2218 authmethod_is_enabled(current)) { 2219 debug3("authmethod_is_enabled %s", name); 2220 debug("Next authentication method: %s", name); 2221 free(name); 2222 return current; 2223 } 2224 free(name); 2225 } 2226 } 2227 2228 static char * 2229 authmethods_get(void) 2230 { 2231 Authmethod *method = NULL; 2232 struct sshbuf *b; 2233 char *list; 2234 int r; 2235 2236 if ((b = sshbuf_new()) == NULL) 2237 fatal("%s: sshbuf_new failed", __func__); 2238 for (method = authmethods; method->name != NULL; method++) { 2239 if (authmethod_is_enabled(method)) { 2240 if ((r = sshbuf_putf(b, "%s%s", 2241 sshbuf_len(b) ? "," : "", method->name)) != 0) 2242 fatal("%s: buffer error: %s", 2243 __func__, ssh_err(r)); 2244 } 2245 } 2246 if ((list = sshbuf_dup_string(b)) == NULL) 2247 fatal("%s: sshbuf_dup_string failed", __func__); 2248 sshbuf_free(b); 2249 return list; 2250 } 2251